Pumps, when hoses are connected to the pump's vacuum side, create a negative pressure in the hoses for conveying liquids therethrough. Such pumps are subject to the serious problem of loss of prime when air or other gas is trapped within the hose and is drawn into the pump. While this problem exists in many areas of liquid transport, one major area of concern involves the cleaning of debris from swimming pools by suction hoses.
The most common current method for purging the hose of air is to place one end of the hose into the pool and to slip the hose slowly into the pool so that the water can move into and through the hose. If any air should inadvertently be left within the hose, when the hose is attached to the pool pump, and if the air reaches the pump, the pump will be deprimed. Therefore, extreme care and time must be taken to prevent entrapment of air within the hose.
Another method is where the operator's mouth is placed on an end of the hose so that water can be sucked into and through the hose. When the operator moves the hose from his mouth to the skimmer inlet, he must place his hand over the end of the hose to prevent entry of air into it.
In either case, filling of the hose with liquid to purge air therefrom is a lengthy and tiresome process. For a professional pool cleaner, this loss of time translates into a loss of income.
Because most swimming pools have a pool skimmer which is used to clean debris floating on the surface of the water by the pool pump, such a vacuum hose is conventionally coupled to the pump through the skimmer.